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(11) | EP 1 598 233 B1 |
| (12) | EUROPEAN PATENT SPECIFICATION |
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| (54) |
Lane change assist system Vorrichtung zur Spurwechselunterstützung Système d'assistance au changement de voie |
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| Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention). |
[0001] The present invention relates to a lane change assist system according to the preamble of independent claim 1 and a method of assisting a lane change of host vehicle according to the preamble of independent claim 15. Such a lane change assist system and such a method of assisting a lane change of host vehicle can be taken from the prior art document EP 1 332 910 A1.
[0002] Japanese Published Patent Application No. 2003-25868 discloses a lane change assist system which facilitates an entering to an adjacent target lane from a present traveling lane and avoids a radical deceleration on the target lane. This lane change assist system is arranged to control a host vehicle speed at a representative vehicle speed of adjacent vehicles on the target lane, to select one adjacent vehicle whose distance to the host vehicle is the smallest distance to a target inter-vehicle distance which is shorter than an inter-vehicle distance set on the target lane as a preceding vehicle on the target lane, and to start a cruise control relative to the newly selected preceding vehicle when a driver manipulates a lane change switch.
[0003] However, since this known lane change assist system is arranged to bring the host vehicle speed closer to the adjacent vehicle speed on the target lane before the execution of the lane change, there is a problem that the assist of controlling the host vehicle speed at the vehicle speed of the adjacent vehicle is not an effective assist in a situation that it is difficult to ensure a space margin for controlling the host vehicle to the adjacent vehicle speed of the adjacent vehicle on the target lane due to the existence of a preceding vehicle ahead of the host vehicle on the present traveling lane or that a difference between the host vehicle speed and the adjacent vehicle speed is very small. Further, in a situation that a plurality of adjacent vehicles are traveling on the target lane while separately having various inter-vehicle distances and vehicle speeds, respectively, it is difficult to obtain the adjacent vehicle speed uniformly.
[0004] It is an object of the present invention to provide a lane change assist system as indicated above and a method of assisting a lane change of host vehicle as indicated above which provides an effective lane change assist even when the difference in speed between the host vehicle and other vehicles on an adjacent target lane is small. According to the apparatus aspect of the present invention said object is solved by a lane change assist system having the features of independent claim 1. Preferred embodiments are laid down in the dependent claims. Furthermore, according to the method aspect of the present invention said object is solved by a method of assisting a lane change of host vehicle having the features of independent claim 15.
[0005] Accordingly it is provided a lane change assist system which comprises: a host vehicle state detecting device that detects a traveling condition of a host vehicle; a surrounding vehicle detecting device that detects other vehicle located around the host vehicle; a lane detecting device that detects a lane around the host vehicle; and a processing unit that is arranged to set a target lane to which the host vehicle change a traveling lane from the detected lane, to determine a start and an ending of a lane change assist, to set a predicted period for an evaluation of a lane change to the target lane, on the basis of a prediction, to obtain an appropriate speed range in which the host vehicle is capable of executing the lane change during the predicted period for each of gaps between other vehicles traveling on the target lane, and to select a target vehicle speed of the host vehicle from the appropriate speed range.
[0006] Another aspect of the present invention resides in a method of assisting a lane change of a host vehicle, which comprises: an operation of detecting a traveling condition of a host vehicle; an operation of detecting other vehicle located around the host vehicle; an operation of detecting a lane around the host vehicle; an operation of executing a setting of a target lane to which the host vehicle moves and a determination of a start and an ending of a lane change assist; an operation of setting a predicted period for an evaluation of a lane change to the target lane on the basis of a prediction; an operation of obtaining an appropriate speed range in which the host vehicle is capable of executing the lane change during the predicted period for each of gaps between other vehicles traveling on the target lane; and selecting a target vehicle speed of the host vehicle from the appropriate speed range.
Hereinafter, the present invention is illustrated and explained by means of preferred embodiments in conjunction with the accompanying drawings. In the drawings wherein:
[0007] Fig. 1 is a schematic view showing a vehicle equipped with a lane change assist system of a first embodiment according to the present teaching.
[0008] Fig. 2 is a block diagram showing a functional construction of the lane change assist system of the first embodiment.
[0009] Fig. 3 is a flowchart showing a processing executed at a processing unit of the lane change assist system of the first embodiment. range in which the host vehicle is capable of executing the lane change during the predicted period for each of gaps between other vehicles traveling on the target lane, and to select a target vehicle speed of the host vehicle from the appropriate speed range.
[0010] Another aspect of the present invention resides in a method of assisting a lane change of a host vehicle, which comprises: an operation of detecting a traveling
[0011] Fig. 6 is a flowchart showing a processing for calculating an appropriate speed range of the first embodiment.
[0012] Fig. 7 is a view showing a situation of setting gaps between other vehicles on an adjacent lane.
[0013] Fig. 8 is a graph showing a lane changeable condition for a gap G0 of Fig. 7 in the first embodiment.
[0014] Fig. 9 is a graph showing a lane changeable condition for a gap G1 of Fig. 7 in the first embodiment.
[0015] Fig. 10 is a graph showing a lane changeable condition of a gap G2 of Fig. 7 in the first embodiment.
[0016] Fig. 11 is a calculation example as to the appropriate speed range and a target vehicle speed in the first embodiment.
[0017] Figs. 12A, 12B and 12C are display examples displayed by a display unit of the first embodiment.
[0018] Fig. 13 is a schematic view showing a vehicle equipped with the lane change assist system of a second embodiment according to the present teaching.
[0019] Fig. 14 is a block diagram showing a functional construction of the lane change assist system of the second embodiment.
[0020] Fig. 15 is a view showing a situation in which the host vehicle equipped with the lane change assist system of the second embodiment is encountered.
[0021] ] Fig. 16 is a flowchart showing a processing for controlling an assist operation of the second embodiment.
[0022] Fig. 17 is a block diagram showing a functional construction of the lane change assist system of a third embodiment.
[0023] Fig. 18 is a flowchart showing a processing executed by the processing unit of the third embodiment.
[0024] Fig. 19A is a graph showing recommended control inputs produced by the lane change assist system of the third embodiment, and Fig. 19B is a displayed example displayed by the display unit of the third embodiment.
[0025] Hereinafter, there is discussed embodiments according to the present invention with reference to the drawings. In the drawings, elements having the same function is denoted by the same reference numeral and the explanation thereof is omitted herein.
[First Embodiment]
[0026] Referring to Figs. 1 through 12, there is discussed a first embodiment of a lane change assist system and a method thereof.
[0027] Fig. 1 is a schematic view of the lane change assist system, which a host vehicle 10 is equipped with. The lane change assist system comprises a forward radar 1a, a rearward radar 1b, a sideward sensor 1c, a lane marker (white line) sensor 1d, a vehicle speed sensor 2, a processing unit 3, a display unit 4, and a turn indicator 5.
[0028] Forward radar 1a is installed at a front portion of host vehicle 10 and measures distances of a plurality of vehicles ahead of host vehicle 10. Rearward radar 1b is installed at a rear portion of host vehicle 10 and measures distances of a plurality of vehicles at the back of host vehicle 10. Sideward sensors 1c are installed at left and right sides of host vehicles, respectively and detect a position of an adjacent vehicle located sideward of host vehicle 10. A radar may be employed as sideward sensors 1c, and an ultrasonic sensor or image sensor may be employed as sideward sensors 1c. These surrounding sensors 1a through 1c function as surrounding vehicle detecting means. Lane marker sensor 1d is constructed by a CCD (charge-coupled device) camera. Lane marker sensor 1d is installed at a front proper portion of host vehicle 10 and detects white lines (lane markers) drawn on a road around host vehicle 10. Lane marker sensor 1d functions as lane detecting means and recognizes a traveling lane from the detected lane markers.
[0029] Vehicle speed sensor 2 is one of vehicle state detecting means and is constructed by installing a rotary encoder at a wheel of host vehicle 10. Vehicle speed sensor 2 generates a cyclic pulse train according to a revolution speed of the wheel and calculates a vehicle speed of host vehicle 10 from the outputted pulse train.
[0030] Processing unit 3 is constructed by a microcomputer and peripheral devices thereof and processes signals outputted from sensors 1a, 1b, 1c, 1d and 2 by executing programs stored in internal memories thereof. The calculation result based on the signals is sent to display unit 4.
[0031] Display unit 4 is constructed by a display processing circuit and a display such as a liquid crystal panel, and displays assist information sent from processing 3. Display unit 4 further comprises a speaker and provides the assist information in the form of sound by replaying previously recorded sounds through the speaker.
[0032] Turn indicator 5 comprises a lever which is cable of being selectively placed at a right turn position, a left turn position and a neutral position through a driver's manipulation. By placing the lever at right turn position or left turn position, turn indicator 5 is lighted up and sends the driver's turn intent and a direction of the changed lance to processing unit 3.
[0033] Processing unit 3 is constructed by blocks 3a, 3b, 3c and 3d shown in Fig. 2, in the form of software and executes the processing through the execution of a flowchart shown in Fig. 3.
[0034] [ As shown in Fig. 2, processing unit 3 comprises an assist operation controlling means 3a, a prediction interval (period) setting means 3b, an appropriate speed range calculating means 3c and a target speed setting means 3d. A reference numeral 30 denotes a vehicle-group state quantity which is a signal sent from lane marker sensor 1d functioning as a lane detecting means, surrounding vehicle detecting sensors 1a through 1c functioning as a surrounding vehicle detecting means, and vehicle speed sensor 2 functioning as a host vehicle state detecting means.
[0035] Hereinafter there is discussed a content of the processing executed at each block of processing unit 3, on the basis of the operation under a situation shown in Fig. 4.
[0036] Fig. 4 represents a situation that two other vehicles 11 and 12 are traveling on a right lane of a one-side two-lane road and host vehicle 10 and one other vehicle 13 ahead of host vehicle 10 is traveling on a left lane of the road. Under this situation, the driver of host vehicle 10 intended to execute a lane change from the left lane to the right lane and manipulates turn indicator 5 to turn on a right turn lamp, but the driver hesitated to execute the lane change due to the existence of other vehicles 11 and 12 on the right lane.
[0037] A coordinate system employed in Fig. 4 is constructed by an x-axis which extends along the traveling direction of vehicles 10 through 13 and on the lane marker (white line) of separating the right and left lanes and a y-axis which is normalized such that an origin of the coordinate system is positioned on the lane marker, a center of the left lane is 1 and a center of the right lane is -1. In this coordinate system, x-coordinates of vehicles 10, 11, 12 and 13 are represented by x0, x1, x2, and x3, respectively. Vehicle speeds of vehicles 10, 11, 12 and 13 are represented by v0, v1, v2, and v3, respectively. y-coordinates of vehicles 10, 11, 12 and 13 are represented by y0, y1, y2, and y3, respectively.
[0038] Processing unit 3 executes the processing represented by the flowchart shown in Fig. 3 at predetermined time intervals.
[0039] At step S1 processing unit 3 reads the signals detected by sensors 1a through 1d and 2 and stores them in its memory. The surrounding information of the read signal is converted in the coordinate system shown in Fig. 4 and stored in a memory of processing unit 3. More specifically, the y-coordinate y0 of host vehicle 10 is determined on the basis of the signal obtained by lane marker sensor 1d. The y-coordinates y1, y2 and y3 of other vehicles 11 through 13 are determined on the basis of lateral-directional relative positional differences of other vehicles 11 through 13 relative to host vehicle 10, which differences are the signals obtained by surrounding sensors 1a through 1c. Further, the x-coordinates x1, x2 and x3 of other vehicles 11 through 13 are determined on the basis of inter-vehicle distances of other vehicles 11 through 13 relative to host vehicle 10, which distances are the signals obtained by surrounding sensors 1a through 1c, and the x-coordinate x0 of host vehicle 10. The vehicle speeds v1, v2 and v3 of other vehicles 11 through 13 are determined by adding host vehicle speed v0 to the respective relative speeds of other vehicles 11 through 13 which are obtained from surrounding sensors 1a through 1c. The obtained information is stored as vehicle-group state quantity 30 of the surrounding vehicles.
[0040] At step S2 processing unit 3 reads a signal indicative of a manipulated state of turn indicator 5. Since turn indicator 5 is manipulated to turn on the right turn lamp in the situation shown in Fig. 4, the information indicative of the right turn state is stored in the memory of processing unit 3.
[0041] At step S3 processing unit 3 determines whether or not it is necessary to produce assist information as to the lane change by calling a program of assist operation controlling means 3a which is one of the processing blocks of processing unit 3. Fig. 5 shows a flowchart of a processing executed at assist operation controlling means 3a.
[0042] At step S31 in Fig. 5 a signal indicative of the manipulation state of turn indicator 5 is checked. When turn indicator 5 is put in off state, the program directly proceeds to step S35 wherein it is determined that no lane change assist is executed, and then the present routine is terminated.
[0043] When turn indicator 5 is put in a right turn state, the program proceeds to step S32 wherein information y0 indicative of the lane position of host vehicle 10 is checked. When y0>0 (affirmative determination) at step S32, it is determined that host vehicle 10 travels on the left lane, and the program proceeds to step S34 wherein the assist for the right lane change is executed. Thereafter the present routine is terminated. When y0≤0 (negative determination) at step S33, the program proceeds to step S35 wherein it is determined that no lane change assist is executed, and the present routine is then terminated.
[0044] When turn indicator 5 is put in a left turn state, the program proceeds to step S33 wherein information y0 indicative of the lane position of host vehicle 10 is checked. When y0<0 (affirmative determination) at step S33, it is determined that host vehicle 10 travels on the right lane, and the program proceeds to step S36 wherein the assist for the left lane change is executed. Thereafter the present routine is terminated. When y0≥0 (negative determination) at step S33, the program proceeds to step S35 wherein it is determined that no lane change assist is executed, and the present routing is then terminated.
[0045] When it is determined that no lane change assist is executed at step S3 in Fig. 3, the program jumps to step S7 wherein a control signal indicative that no lane change assist is executed is outputted to display unit 4 to display the information of not executing lane change assist. Thereafter, the present routine of Fig. 3 is terminated.
[0046] When it is determined that the lane change assist is executed at step S3, the program in Fig. 3 proceeds to step S4 wherein the processing of prediction interval setting means 3b is executed and therefore a future predicted period for the appropriate speed calculation executed at step S5. The predicted period is set at a time period from the present time t to a future time t+T(t-t0) which is a time elapsed from the present time t by a time period T(t-t0), and a function T is defined as follows.
where T0 is an initial prediction time period, Tmin is a lower limit of the prediction time period, and both of them are parameter determined by a designer of this system. Hereinafter, T(t-t0) is basically denoted by T, and the prediction time interval is basically denoted by a set period [t, t+T].
[0047] At step S5 the processing of appropriate speed range calculating means 3c is called, and there is executed the calculation of an appropriate speed range which is necessary for host vehicle 10 to change the lane to each gap between other vehicles on the target lane with a predetermined margin. With reference to a flowchart of Fig. 6, there is discussed the processing of appropriate speed range calculating means 3c.
[0048] At step S51 in Fig. 6, processing unit 3 determines a number N of other vehicles traveling on the target lane and labels each gap between other vehicles in the order of 0 to N from the front side of other vehicles. Processing unit 3 determines whether or not the detected other vehicles are traveling on the target lane on the basis of the y-coordinate of each other vehicle. More specifically, under the situation shown in Fig. 4, the determination that other vehicle i (i is an integer specifying other vehicle) is traveling on the target lane (right lane) can be made by checking the condition that yi<0. In case of Fig. 4, since it is determined that other vehicles 11 and 12 are traveling on the target lane, the number N of other vehicle on the target lane is set at 2 (N=2), and therefore gaps G0, G1 and G3 are set as three lane-change candidates as shown in Fig. 7.
[0049] At step S52 processing unit 3 initializes the index for sequentially evaluating the gaps at 0.
[0050] At step S53 processing unit 3 executes a calculation of an appropriate speed range for gap G0 located at the foremost position of gaps G0, G1 and G2. In order to define the appropriate vehicle speed for the lane change, an appropriate lane change condition as to a positional relationship and a speed relationship between other vehicle 11 and host vehicle 10 is set. An inter-vehicle distance R and a relative speed Ṙ between other vehicle 11 and host vehicle 10 are defined using the following expressions (2) and (3).
[0051] As a condition of the inter-vehicle distance and the relative speed appropriate for the lane change to gap G0, the following conditions expressed by the following expressions (4) and (5) are employed.
[0052] The expression (4) represents a condition requesting that host vehicle 10 travels a position ahead of other vehicle 11 by a headway time hmin or more. The expression (5) represents a condition requesting that a collision time (inter-vehicle distance/relative speed) is greater than or equal to TTCmin as a margin. Both of hmin and TTCmin are design parameters designed by the designer of the lane change assist system. Fig. 8 shows the state satisfying the above two conditions.
[0053] By assuming that the vehicle speeds of host vehicle 10 and other vehicle 11 are constant within the predicted period, it becomes possible to calculate a change of the state quantity indicative of a relationship between host vehicle 10 and other vehicle 11 on a plane (Ṙ, R). A value Ṙ represents a time differential of R. Fig. 8 shows loci of points on the plane (Ṙ, R), which represent state quantities as to three speeds that the vehicle speed of host vehicle 10 is set at
and
.
[0054] A host vehicle speed by which the state quantity reaches the range indicative of the lane changeable condition within the predicted period is defined as an appropriate speed for gap G0. In case of Fig. 8, host vehicle speed v
is the appropriate speed for gap G0, and host vehicle speeds
and
are not the appropriate speed for gap G0. A set of the appropriate speeds is defined as an appropriate speed range.
[0056] When R(t) ≥ -hmin v1, the lane changeable condition at time t+T is R(t + T) < -hmin v1. When the host vehicle speed of host vehicle 10 is
a prediction value R̂(t + T) of R at time t+T is calculated from the following expression (6).
where R̂ represents a prediction value of R differential
[0057] From the relationship of R̂(t + T) < -hmin v1, the following condition expressed by the expression (7) is obtained
[0058] When R(t) < -hmin v1, the lane changeable condition is satisfied as far as satisfying the condition expressed by the expression (5). Therefore, under this situation, the following condition expressed by the expression (8) is obtained
[0059] From the above conditions, the appropriate speed range V0 for gap G0 is obtained from the following expression (9).
[0060] At step S54 the index is incremented by 1. At step S55 it is checked whether or not the index reached N-1. When the index reaches N-1, the program proceeds to step S57. When the index does not reach N-1, the program proceeds to step S56.
[0061] At step S56, processing unit 3 calculates the appropriate speed range for executing a lane change to move the gap Gi (i is zero or positive integer) between other vehicles. In the example shown in Fig. 4, gap G1 corresponds to the gap Gi. Hereinafter, there is discussed a concrete calculation method of the appropriate speed range for gap G1 produced between other vehicles 11 and 12. Even when the number N is greater than or equal to 3, by replacing other vehicles 11 and 12 with a forward vehicle and a rearward vehicle between which a gap is produced.
[0062] An appropriate lane change condition for gap G1 corresponding to the expressions (4) and (5) is set by the following expressions (12) and (13) based on the expressions (10) and (11).
[0063] In order to simplify the above expressions (10) through (13), a new coordinate system (x̅, v̅) is employed. There is assumed an inertia coordinate system which continues a uniform motion at a speed {v1(t)+v2(t)}/2 relative to the ground x-coordinate. More specifically, there is assumed a coordinate system represented by the following transformations (14) through (17).
[0064] There is shown a phase plane view representing the conditions of the expressions (10) through (14) on the plane (x̅, v̅) in Fig. 9.
[0065] When a condition defined by the following expression (18) is satisfied, there is no point of simultaneously satisfying the expressions (10) and (11) in the space including gap G1. Therefore, in this condition satisfying the expression (18) it is determined that it is impossible to execute the lane change to gap Gi, and the appropriate speed range thereof is treated as an empty set.
[0066] As is similar to Fig. 8, the loci of the state quantities in the phase plane are determined from the host vehicle speed of host vehicle 10. If the state quantity reaches a parallelogram zone representing a lane changeable condition within the predicted period, it is similarly determined that it is possible to execute the lane change. In the example of Fig. 9, it is determined that the host vehicle speed
is an appropriate speed for the lane change to gap G1, the host vehicle speeds
and
are not the appropriate speed for the lane change to gap G1. More specifically, the concrete value of the appropriate speed range is calculated as follows.
[0067] In case that
the lane changeable condition for determining that the lane change can be executed is represented by the following expressions (19) and (20)
where the prediction values of the coordinates of host vehicle 10 and other vehicle 12 at time t+T are represented as
and
respectively.
[0068] Under the condition that host vehicle speed
of host vehicle 10 and vehicle speed
of other vehicle 12 are constant, the prediction values of the coordinates of host vehicle 10 and other vehicle 12 at time t+T are represented by the following expressions (21) and (22).
[0069] Therefore, the lane changeable condition of host vehicle speed
is represented by the following expression (23) from the expressions (19), (20) and (21)
[0070] By returning the present coordinate to a normal coordinate, a condition equivalent to the expression (23) is expressed by the following expression (24)
[0071] Similarly, by returning the present coordinate to the normal coordinate a condition equivalent to the expression (20) is expressed by the following expression (25)
[0073] In case that
the lane changeable condition for determining that the lane change can be executed is represented by the following expressions (27) and (28)
[0074] By obtaining the appropriate speed range of the case [2] in the same manner of the case [1], the appropriate speed range is expressed by the following expression (29).
[0075] In case that
the condition satisfies at least a condition that the target vehicle speed is in the lane changeable condition represented by the parallelogram. Since the conditions (10) and (11) are already satisfied from the assumption, the appropriate speed range is expressed by the following expression (30) obtained by solving the inequalities (12) and (13).
[0076] By sorting the above discussed contents, the following expression (31) is obtained as the appropriate speed range V1 for gap G1.
[0077] These calculations are repeatedly executed from i=1 to i=N-1 to calculate the appropriate speed range Vi for each gap Gi.
[0078] At step S57 an appropriate speed range for gap GN located at a rearmost position is obtained. With reference to Fig. 4, the explanation of this calculation is explained.
[0079] An inter-vehicle distance and a relative speed between the host vehicle 10 and other vehicle 12 producing gap GN are defined by the following expressions (32) and (33) as similar to the expression (2) and (3).
[0080] As a condition for the inter-vehicle distance and a relative speed appropriate for the lane change to gap GN, the following two conditions expressed by the following expressions (34) and (35) are employed.
[0081] The condition of satisfying the expressions (34) and (35) is represented by Fig. 10. Fig. 10 shows loci of points on the plane (Ṙ, R), which represent state quantities as to three speeds which are the vehicle speed of host vehicle 10 and are set at
,
and
, respectively.
[0082] A host vehicle speed by which the state quantity reaches the range indicative of the lane changeable condition within the predicted period is defined as an appropriate speed for gap G0. In case of Fig. 10, host vehicle speed
is the appropriate speed for gap G0, and host vehicle speeds
and
are not the appropriate speed for gap G0.
[0084] When R(t)≥hminv0, the lane changeable condition at time t+T is R(t+T)>hminv0. From the relationship of R̂(t+T)<-hminv0, the following condition expressed by the expression (36) is obtained.
[0085] When R(t)<hminv0, the lane changeable condition is satisfied as far as satisfying the condition expressed by the expression (35). Therefore, under this situation, the following condition expressed by the expression (37) is obtained.
[0086] From the above conditions, the appropriate speed range v0 for gap G0 is obtained from the following expression (38).
[0087] At step S58, it is checked whether or not a preceding vehicle is traveling ahead on host vehicle 10 on the traveling lane. For example, in case that host vehicle 10 is traveling on the left lane, a condition that yi > 0 and xi < x0 is set to determine that other vehicle i is a preceding vehicle ahead of host vehicle 10 on the traveling lane. In other vehicles satisfying one of the above two inequalities, other vehicle taking the minimum value of xi is a preceding vehicle ahead of host vehicle 10 on the traveling lane. In Fig. 4, other vehicle 13 corresponds to the preceding vehicle. When the preceding vehicle is detected, the program proceeds to step S59. When the preceding vehicle is not detected, the program proceeds to step S60.
[0088] At step S59, there is executed a correction of eliminating an improper speed range, by which it is difficult to ensure a suitable margin of the inter-vehicle distance by the lane change completion, from the calculated appropriate speed ranges V0 through VN. With reference to Fig. 4, there is explained this correction process.
[0089] First, the inter-vehicle distance and the relative speed relative to the preceding vehicle are defined as follows.
[0090] On the assumption that the speed of the preceding vehicle is constant, it is requested that the inter-vehicle distance and the relative speed satisfy the following expressions (33) and (34), respectively.
[0091] Since R̂(t+T) is calculated in the same manner of the expression (6), the expressions (41) and (42) are expressed by the following expressions (43) and (44).
[0092] Accordingly, the appropriate speed range having the margin of the inter-vehicle distance relative to the preceding vehicle is set by the following expression (45).
[0093] By setting the intersection V0 ∩ VP,···, VN ∩ VP of the appropriate speed ranges V0 through VN of the respective gaps relative to the appropriate speed range VP as the new appropriate speed range, the correction of the appropriate speed range is executed.
[0094] At step S60, the correspond of the appropriate speed range is executed on the basis of the upper limit and the lower limit of the speed range. More specifically, on the basis of the upper limit Vmax and the lower limit Vmin of the target vehicle speed which have been determined with reference to a driving operation characteristic of general drivers, the appropriate speed range VL based on the upper and lower limits is defined as follows.
[0095] By setting the intersection V0 ∩ VL,···,VN ∩ VL of the appropriate speed ranges V0 through VN of the respective gaps relative to the appropriate speed range VL as the new appropriate speed range, the correction of the appropriate speed range is executed.
[0096] At step S6 processing unit 3 obtains the target vehicle speed appropriate for the lane change by comparing the calculated appropriate speed range with the present host vehicle speed. For example, the calculation result as to the appropriate speed range in the case of Fig. 4 is shown in Fig. 11. Since gap G0 does not satisfy the preceding vehicle limitation, it is determined that gap G0 is not put in the lane changeable condition. Gaps G1 and G2 include the appropriate speed range. The present host vehicle speed is at the intermediate position between the appropriate speed range for gap G1 and the appropriate speed range for gap G2. It is predicted that it is difficult to execute the lane change during the predicted period with the margin while maintaining the host vehicle speed. Under this condition, the gap whose appropriate speed range includes the nearest factor to the host vehicle speed is selected as the gap to which the host vehicle is moved by the lane change, by comparing the host vehicle speed and the appropriate speed range. Further, the nearest factor to the host vehicle speed is set at the target vehicle speed, or the point offset from the boundary of the appropriate speed range toward the center of the appropriate speed range by a proper margin Δv may be set at the target vehicle speed.
[0097] When the host vehicle speed is within the appropriate speed range for one of the gaps, the present host vehicle speed is directly set at the target vehicle speed. As a setting method of the target vehicle speed, there may be employed other method except for the setting method of setting the target vehicle speed on the smaller difference between the host vehicle speed and the appropriate speed range. For example, in case that it is intended to change the lane to the forward-most position as possible, the target vehicle speed is set at the maximum speed in the appropriate speed range. Further, when the appropriate speed range becomes an empty set, an appropriate vehicle speed for traveling the present traveling lane and not for executing the lane change is selected from the appropriate speed range VP determined by the preceding vehicle limitation as a provisional target speed. More specifically, when the present host vehicle speed is in the appropriate speed range VP, the present host vehicle speed is set as the provisional target vehicle speed. When the present host vehicle speed is not in the appropriate speed range VP, the maximum vehicle speed in the appropriate speed range VP is set as the provisional target vehicle speed. When the appropriate speed range VP is not defined due to the inexistence of the preceding vehicle ahead of the host vehicle in the traveling lane, the present host vehicle speed is set as the provisional target vehicle speed.
[0098] At step S7 a command signal for displaying the target vehicle speed set at step S6 on display unit 4 is generated and sent to display unit 4. When the appropriate speed range is an empty set, a display signal indicative that there is no appropriate speed range for the lane change is generated and sent to display unit 4. When it is determined at step S3 that it is not necessary to execute the lane change assist operation, a signal indicative of the unnecessary state of the lane change assist is generated and sent to display unit 4.
[0099] Display unit 4 displays the information as to the lane change assist according to the command signal sent from processing unit 3. Figs. 12A, 12B and 12C show examples of displayed contents on display unit 4. As understood from Figs. 12A through 12C, display unit 4 displays the manipulation state of turn indicator 5 and the calculated target speed. Simultaneously an arrow which shows whether the present host vehicle speed is higher or lower than the target vehicle speed so that the driver can understand the relationship between the host vehicle speed and the target vehicle speed without conscious deductive effort. Further, when no lane changeable gap is found, the displayed provisional vehicle speed is flashed and an alarm sound is generated to strongly inform this lane unchangeable state to the driver. When it is not necessary to execute the lane change assist, no information is generated.
[0100] The lane change assist system of the first embodiment according to the present teaching comprises vehicle speed sensor 2 functioning as the host vehicle state detecting means for detecting the traveling state of host vehicle 10, the surrounding vehicle detecting means 1a, 1b and 1c for detecting other traveling vehicles around host vehicle 10, lane marker detecting sensor 1d functioning as lane detecting means for detecting lanes around host vehicle 10, assist operation controlling means 3a for setting the target lane to which host vehicle 10 is lane changed and for determining the start and the ending of the lane change assist operation, predicted period setting means 3b for setting the predicted period of evaluating the possibility of the lane change on the basis of the prediction, appropriate speed range calculating means 3c for calculating the appropriate speed range appropriate for the lane change of host vehicle 10, and target vehicle speed setting means for setting the target vehicle speed of host vehicle 10.
[0101] The lane change assist method discussed in the first embodiment according to the present teaching comprises a step for detecting the traveling state of host vehicle 10, a step for detecting surrounding vehicles traveling around host vehicle 10, a step for setting the target lane to which host vehicle 10 executes the lane change and for determining the start and the ending of the lane change assist operation, a step for setting the predicted period of evaluating the possibility of the lane change on the basis of the prediction, a step for calculating the appropriated speed range appropriate for the lane change of host vehicle 10, and a step for setting the target vehicle speed of host vehicle 10.
[0102] The first embodiment according to the present teaching is arranged to obtain the speed range appropriate for the lane change to each gap generated by other vehicles traveling on the target lane and to calculate the target vehicle speed for host vehicle 10 base on the appropriate speed range. That is, the target vehicle speed is not the vehicle speed of the adjacent vehicle and is determined based on the appropriate speed range appropriate for the lane change. Accordingly even when a difference between the host vehicle speed and the vehicle speed of the vehicle in the target lane is small or zero, an appropriate speed for easy executing the lane change is obtained by intently producing the difference between the host vehicle speed and the vehicle speed of the vehicle in the target lane. Further, even when a plurality of other vehicles are traveling on the target lane, the lane change assist system of the first embodiment according to the present teaching calculates the appropriate speed ranges for the respective gaps generated by the plurality of other vehicles in the target lane. Accordingly, even if the driver selects any gap as the target gap of the lane change, the target vehicle speed appropriate for the lane change is obtained according to the traveling states of the other vehicles producing the target gap.
[0103] Assist operation controlling means 3a of processing unit 3 is arranged to set the target lane and to determine the start and the ending of the lane change assist operation on the basis of the manipulation of turn indicator 5 by the driver. That is, by controlling the operation of the lane change assist system while interlocking with the manipulation of turn indicator 5 which is a standard device for informing the lane change intent of the driver, the lane change assist system functions to provide the lane change assist information to the driver without requesting a special driver's manipulation.
[0104] Appropriate speed range calculating means 3c is arranged to calculate the appropriate speed range for each gap on the basis of the inter vehicle distances and the relative speeds to the preceding vehicle ahead of host vehicle 10 on the traveling lane and to the other vehicles which produce the gaps on the target lane. Since the appropriate speed range is obtained taking account of the preceding vehicle ahead of host vehicle 10 on the traveling lane in addition to the other vehicles producing the gaps on the target lane, the speed range requiring the excessive approach to the preceding vehicle for the lane change to the target gap is eliminated from the appropriate speed range. This arrangement provides a further realizable appropriate speed range.
[0105] Appropriate speed range calculating means 3c is further arranged to calculate the appropriate speed range within a range between the upper limit and the lower limit which have been previously set. This limitation of the appropriate speed range prevents an improper lane change assist that the target vehicle speed is set at an improper high vehicle speed refused by the driver's sense or at an extremely low vehicle speed which prevents the smooth driving.
[0106] Target vehicle speed setting means 3d is arranged to set the target vehicle speed by employing a condition that a difference of the speed in the appropriate speed range relative to the host vehicle speed is small, as one of the target vehicle speed selecting condition. With this arrangement, the target vehicle speed is selected from the appropriate speed range with reference to the present vehicle speed of host vehicle 10. Therefore, this arrangement sets the target vehicle speed without requesting the radical acceleration or radical deceleration as possible.
[0107] Display unit 4 for displaying the speed guidance for the driver is arranged to display the target vehicle speed calculated at target speed setting means 3d. The lane change assist system is thus arranged to display an example of the target vehicle speed appropriate for the lane change so as to assist the driver's diagnosis as to the lane change.
[0108] Further, the lane change assist system comprises alarm means for generating an alarm for the driver so as to inform the inappropriate state of the lane change to the driver when target vehicle speed setting means 3d determines that the appropriate speed range is an empty set. This arrangement also assists the driver's state diagnosis for the lane change positively.
[Second embodiment]
[0109] Referring to Figs. 13 through 16, there is discussed a second embodiment of the lane change assist system according to the present teaching.
[0110] Fig. 13 is a schematic view of the lane change assist system which host vehicle 10 is equipped with.
[0111] The lane change assist system of the second embodiment comprises a forward radar 1a, a rearward radar 1b, a sideward sensor 1c, a lane marker (white line) sensor 1d, a vehicle speed sensor 2, a processing unit 3, a display unit 4, a turn indicator 5, a GPS (Global Positioning System) signal receiver 6, map information database 7, a throttle controller 8, a throttle actuator 9 and an engine 14.
[0112] The lane change assist system of the second embodiment specially comprises GPS signal receiver 6, map information database 7, throttle controller 8, throttle actuator 9 and engine 14 in addition to the arrangement of the first embodiment.
[0113] GPS signal receiver 6 receives a GPS signal and calculates a present position of host vehicle 10 based on the GPS signal. GPS signal receiver 6 identifies a present traveling road of host vehicle 10 by verifying the present position based on the GPS signal and the information stored in map information database 7. Further, when it is determined that the traveling lane is decreased ahead of host vehicle 10 from the information as to the number of lane of the traveling road, which is read from the map information database 7, GPS signal receiver 6 sends the information as to the point of the lane decreased point and the decreased lane to processing unit 3.
[0114] Throttle controller 8 executes a vehicle speed control for bringing the host vehicle speed close to the target vehicle speed by controlling the output of engine 14 through the control of the throttle opening using throttle actuator 9 on the basis of the target vehicle speed commanded by processing unit 3 and the present host vehicle speed.
[0115] By the addition of the above discussed devices, processing unit 3 of the second embodiment is constructed as shown in Fig. 14.
[0116] Basic construction and processing procedure executed by processing unit 3 are basically the same as those of the first embodiment, except that processing unit 3 newly comprises a lane decreased point detecting means constructed by GPS signal receiver 6 and map information database and a vehicle speed control means constructed by throttle controller 8, throttle actuator 9 and engine 14.
[0117] As shown in Fig. 14, the functions constructed by software in processing unit 3 are basically divided into four blocks and are basically executed as shown by the flowchart in Fig. 3. The contents of each block and each step are slightly changed, and therefore the changed parts are explained hereinafter.
[0118] At step S1 in Fig. 3, the processing unit 3 receives GPS signal from GPS signal receiver 6 and execute the map matching with map information database 7, in addition to receiving the signals of surrounding sensors 1a through 1c and vehicle speed sensor 2. In case that the number of lanes of the traveling road is soon decreased as shown in Fig. 15, processing unit 3 calculates the information of the x-coordinate xend (traveling-direction coordinate) at the lane decreased point and the direction of the decreased lane toward the left lane or right lane. The x-coordinate xend of the lane decreased point is set at a point nearer than the actual lane decreased point relative to host vehicle 10 so as to execute the lane change with a margin.
[0121] In the second embodiment, processing unit 3 determines with reference to the information as to the lane decreased point whether or not it is necessary to execute the lane change assist before checking the manipulation of turn indicator 5.
[0122] At step S131 in Fig. 16, it is determined whether or not host vehicle 10 is approaching the lane decreased point. More specifically, using the following expression (47), the determination as to the approach to the lane decreased point is executed.
where RMIC is a determination threshold.
[0123] When the determination at step S131 is affirmative, that is, when the expression (47) is satisfied, the program proceeds to step S132. When the expression (47) is not satisfied, the program proceeds to step S134.
[0124] At step S132 it is determined whether or not the traveling lane corresponds to the decreased lane. When determination at step S132 is negative, host vehicle 10 may keep the traveling lane without executing the lane change, and the program proceeds to step S134. When the determination at step S132 is affirmative, that is, when the traveling lane corresponds to the decreased lane, it is necessary to execute the lane change and therefore the program proceeds to step S133.
[0125] At step S133 it is determined whether host vehicle 10 has to turn to the right or left on the basis of the information obtained at step S1. When host vehicle 10 has to change the traveling lane to the right lane, the program jumps to step S137. When host vehicle 10 has to change the traveling lane to the left lane, the program jumps to step S139. The processing contents of steps S134 through S139 are completely the same as those of steps S31 through S36 shown in Fig. 5, respectively. Therefore the explanation thereof is omitted herein.
[0126] At step S4 the predicted period is set. In the first embodiment, host vehicle 10 is put in the situation that it is possible to continue the traveling of the present traveling lane if the condition for the lane change is not suitable as shown in Fig. 4. Therefore, it is possible to extend the execution of the lane change by setting the lower limit of the predicted period. However, in the second embodiment, the lane change assist system is arranged to adapt to the case shown in Fig. 15. In case of Fig. 15 it is necessary to certainly complete the lane change before host vehicle 10 reaches the lane decreased point. Therefore, it is improper to set the lower limit of the predicted period. Therefore, processing unit 3 of the second embodiment sets the predicted period using the following expression (48) in the processing at step S4. That is, the predicted period is set at a time period taken by reaching the lane decreased point under the constant vehicle speed of keeping the present host vehicle speed.
[0127] The calculation procedure of the appropriate speed range executed at step S5 of the second embodiment is completely the same as that of the first embodiment.
[0128] The calculation procedure of the target speed executed at step S6 is basically the same as that of the first embodiment. However, there is no choice of the provisional target vehicle speed which is set when the appropriate speed range is an empty set and host vehicle 10 suspends the lane change, at the point before the lane decreased point shown in Fig. 15. Therefore, when the appropriate speed range for the lane change is not found, the target vehicle speed is set at a vehicle speed by which host vehicle 10 stops at the lane decreased point upon taking account of a bad case that host vehicle 10 cannot execute the lane change before host vehicle 10 reaches the meeting point of the traveling lane and the adjacent lane. When the maximum deceleration realized by the vehicle speed controlling means is dmax, the maximum value
of the vehicle speed by which host vehicle 10 can stop at the lane decreased point is represented by the following expression (49).
[0130] At step S7, processing unit 3 outputs the command signal to the vehicle speed controlling means in addition to the output signal to display unit 4.
[0131] Processing unit 3 outputs a signal indicative of the target vehicle speed to throttle controller 8 of the vehicle speed controlling means. Throttle controller 8 also receives a signal indicative of the host vehicle speed detected by vehicle speed sensor 2. Throttle controller 8 controls the output of engine 14 by controlling the throttle opening using the throttle actuator 9 so as to correspond a transfer characteristic Gv(s) of the host vehicle speed v0 relative to target vehicle speed
for the vehicle speed control system with a first-order delay system represented by the following expression (51).
where TV is a time constant of the vehicle speed control system.
[0132] Display unit 4 of the second embodiment displays the information similar to that displayed by display unit 4 of the first embodiment.
[0133] With the thus arranged second embodiment according to the present teaching, the lane change assist system is arranged to detect the lane decreased point ahead of host vehicle 10, at which the number of the lanes is decreased. The lane change assist system comprises GPS signal receiver 6 and map information database 7 which function as lane decreased point detecting means for informing the distance to the lane decreased point and the decreased lane. The assist operation controlling means 3a of processing unit 3 is arranged to start the lane change assist operation after the adjacent lane is automatically set as the target lane when the distance between host vehicle 10 and the lane decreased point is smaller than the predetermined distance and host vehicle 10 is traveling on the decreased lane, that is, when host vehicle 10 is put in a forcible lane change condition. Further the assist operation controlling means is arranged to terminate the lane change assist operation when it is determined that the lane change to the target lane is completed. By detecting the situation that host vehicle 10 has to execute the lane change in near future and by automatically starting the lane change assist, the lane change assist system attracts the attention of the driver so that the driver executes the necessary assist operation against the forcible lane change condition.
[0134] Further the lane change assist system of the second embodiment comprises throttle controller 8, throttle actuator 9 and engine 14 which are the vehicle speed controlling means for controlling the host vehicle speed of host vehicle 10 at the target vehicle speed. The vehicle speed controlling means is arranged to control the traveling of host vehicle 10 by inputting the target vehicle speed calculated at the target vehicle speed calculating means 3d as the target value of the vehicle speed control system. Since the vehicle speed control system automatically controls the host vehicle speed at the target vehicle speed, it becomes possible to decrease the driver's load of controlling the vehicle speed during the lane change. Further, the predicted period setting means 3d is arranged to set a time when a target time period elapsed from the start of the lane change assist is set as an ending time of the predicted period and to extend the ending time according to the time elapse when the forcible lane change condition is not satisfied. That is, when host vehicle 10 is put in the situation of allowing host vehicle 10 to continue the traveling on the present traveling lane while the driver desires the lane change, the lane change assist system suppresses the generation of the target vehicle speed which requests the driver to complete the lane change within the short time period, by extending the ending time of the predicted period.
[0135] Further, the predicted period setting means 3b is arranged to set the ending time of the predicted period at an estimated reaching time when host vehicle 10 will reach a point ahead of the lane decreased point by a predetermined distance when the forcible lane change condition is satisfied. By setting the ending time of the predicted period at a time near the time when host vehicle 10 reaches the lane decreased point, it becomes possible to set the target vehicle speed of completing the lane change before host vehicle reaches the lane decreased point with the highest priority.
[0136] With the thus arranged lane change assist system of the second embodiment according to the present teaching , the speed control appropriated for the lane change is automatically executed in the situation that the lane change has to be executed. This arrangement largely assists the lane change operation of the driver.
[0137] Target speed setting means 3d is arranged to set the appropriate speed range at a speed range of avoiding an excessive approach to a preceding vehicle ahead of host vehicle 10 on the present traveling lane and to select a proper target vehicle speed from the appropriate speed range when the appropriate speed range is an empty set and the forcible lane change condition is not satisfied. The target vehicle speed is selected from vehicle speed appropriate to continue the traveling of the present traveling lane under the situation that no appropriate gap for the lane change is found in the target lane. Accordingly, it becomes possible to execute the assist during a waiting period for finding the appropriate gap for the lane change.
[0138] Target speed setting means 3d is arranged to set the target vehicle speed at the vehicle speed enabling host vehicle 10 to stop at a point before the lane decreased point by a deceleration smaller than the predetermined deceleration when the appropriate speed range is an empty set indicative that no gap for the lane change is found and the forcible lane change condition is satisfied. Under this situation that no gap appropriate for the lane change is found at the point nearer to host vehicle 10 than the point at which the lane change has to be executed, the target vehicle speed is set at the vehicle speed of enabling host vehicle 10 to stop before reaching the lane decreased point with a margin. Accordingly, it becomes possible that the lane change assist system requests the driver to execute the stop of host vehicle 10 for awaiting the chance of the lane change without executing the inappropriate lane change in the vicinity of the lane decreased point.
[Third embodiment]
[0139] Referring to Figs. 17 through 19, there is discussed a third embodiment of the lane change assist system according to the present teaching. The construction of the system of the third embodiment is the same as that of the first embodiment.
[0140] Fig. 17 shows a functional block diagram. As shown in Fig. 17, processing unit 3 of the third embodiment further comprises recommended control input producing means (recommend manipulation quantity calculating means) 3e in the form of software. Further, the processing procedure of processing unit 3 of the third embodiment is shown by a flowchart of Fig. 18 wherein a processing of producing a recommended control input (recommended manipulation quantity) is added to as step S207. The processing contents of steps S201 through S206 are completely the same as those of steps S1 through S6, respectively. Therefore the explanation thereof is omitted herein.
[0141] At step S207 in the flowchart of Fig. 18, the processing of producing the recommended control input is executed by executing a calculation method constructed by the following expressions (E1) and (E2), which are disclosed in Japanese Published Patent Application No. 2003-228800. This calculation is executed on the setting discussed hereinafter.
where
and
[0142] First, a prediction expression for predicting behaviors of host vehicle 10 and surrounding vehicles and an evaluation function for mathematically evaluating the control input of host vehicle 10 are defined. In case of the third embodiment of the lane change assist system, the prediction expression for predicting the behavior of the surrounding vehicle is derived by the following manner.
[0143] As a longitudinal motion model of host vehicle 10, a model expressed by the following expressions (52) and (53) is employed.
where ux is an acceleration/deceleration command value of host vehicle 10.
[0144] As a lateral motion mode of host vehicle 10, a mode expressed by the following expression (54) is employed.
[0145] A behavior model of other vehicle i is set by the following expressions (55) (56) and (57).
where the following conditions (58) is required.
[0146] Further, ωi is a parameter representative of a time constant (inverse number) of the vehicle speed control of other vehicle
is a predicted target vehicle speed of other vehicle i, and XP(t) and VP(t) are coordinates indicative of a position and a vehicle speed of a preceding vehicle traveling ahead of other vehicle i on the same lane. For example, in case of Fig. 4, other vehicle 11 corresponds to a preceding vehicle of other vehicle 12. Since no preceding vehicle of other vehicles 11 and 13 is found, it is determined that other vehicles 11 and 13 are not put in a following travel condition. A function
is a modeled function of a target vehicle speed of a vehicle which produces an inter-vehicle distance R and a relative speed Rv relative to the preceding vehicle. It is possible to utilize a control algorism constructed by the following expressions (E3) and (E4), Table 1 representing a relationship among a natural frequency of an inter-vehicle distance control, an inter-vehicle distance difference ΔL and a relative speed ΔV, and Table 2 representing a relationship among a damping coefficient of the inter-vehicle distance control, the inter-vehicle distance difference ΔL and the relative speed ΔV, which are disclosed in Japanese Published Patent Application No. 2000-135934.
where Vt is a vehicle speed of a preceding vehicle.
[0147] As an evaluation function of mathematically evaluating the control input of host vehicle 10, the following function (59) is employed.
where T̅ represents a length of the period of producing the recommended control input, and a function L is a function of evaluating the control input during the recommended control input generating period and the state thereof. X is a state quantity of the system, and in case of Fig. 4, the state quantity X is represented by the following expression (60).
[0148] Recommended control input producing period T̅ has to be set at a value to be long as the driver can recognize it as a pattern of the control input and to be short as the accuracy of the estimation is not so degraded thereby. Therefore, it is substantially set at several seconds.
[0149] The evaluation expression L is constructed by the sum of four functions which represent a first limitation of traveling at the target vehicle speed as possible, a second limitation of preventing a large acceleration/deceleration as possible, a third limitation of avoiding the lane change to be frequently executed, and a fourth limitation of avoiding host vehicle from excessively approaching surrounding vehicles, respectively.
[0150] As a function representing the first limitation, the following function (61) is employed.
where wv is a positive constant representing an evaluation weight relative to the first limitation,
is the target vehicle speed calculated by the target vehicle speed calculating means.
[0151] As a function representing the second limitation, the following function (62) is employed.
where wx is a positive constant representing an evaluation weight relative to the second limitation.
[0152] As a function representing the third limitation, the following function (63) is employed.
where wy is a positive constant representing an evaluation weight relative to the third limitation.
[0153] In order to express the fourth limitation, an evaluation criteria for evaluating a risk relative to surrounding vehicles is employed. As an evaluation criteria, a headway time (inter-vehicle distance/vehicle speed of a following vehicle) and a collision time (inter-vehicle distance/relative speed) are known. The evaluation function (59) is constructed such that smaller the value becomes higher the evaluation becomes. Accordingly, inverse values of the headway time and the collision time are used. The following expression (64) is used as an evaluation expression of the preceding vehicle ahead of host vehicle 10 on the traveling lane, and the following expression (65) is used as an evaluation expression of a rearward vehicle of host vehicle on the traveling lane.
where xf and vf are a position and a vehicle speed of the preceding vehicle (frontward vehicle), xr and vr are a position and a vehicle speed of the rearward vehicle, α is a constant which is for the weights of the headway time and the collision time and takes a value ranging form 0 to 1, and β is a positive constant of determining a shape of a saturation factor employed to limit a lower side of the evaluation function.
[0154] In the case of Fig. 4, when host vehicle 10 is traveling on a left side lane, other vehicle 13 is a preceding vehicle (frontward vehicle). When host vehicle 10 executed the lane change to gap G1 of a right side lane, other vehicle 11 is a preceding vehicle and other vehicle 12 is a rearward vehicle. After host vehicle 10 changed the traveling lane to the right side lane, other vehicles 11 and 12 are evaluated. Accordingly, the fourth limitation is constructed by combining the expressions (64) and (65) and represented by the following expression (66).
where w1, w2 and w3 are positive constants representative of weights of other vehicles 11, 12 and 13, respectively, and function CL(y) and CR(y) are represented as follows.
[0155] In case that host vehicle changes the lane to other gap, the evaluation expression is constructed according to the relationship with frontward and rearward vehicles of host vehicle 10 in the same manner as discussed above.
[0156] The evaluation expression L is constructed by the sum of the expressions (61), (62), (63) and (66) as follows.
[0157] As discussed above, by defining the prediction expressions (52) through (58) and the evaluation function (59), it becomes possible to calculate the control inputs ux and uy of minimizing the evaluation function as time-series signals during a period from a present time T to a future time that the period T̅ elapsed from the time t.
[0158] At step S208 processing unit 3 generates an output signal and outputs the signal to display unit 4.
[0159] Display unit 4 displays the information according to the display command signal sent from processing unit 3. Fig. 19A shows the generated recommended control inputs generated in the situation that host vehicle is put in the condition shown in Fig. 4 and the target vehicle speed was selected from the appropriate speed range for gap G2. Fig. 19B shows a display content displayed by display unit 4 in this situation.
[0160] In this situation, the target vehicle speed of host vehicle 10 is set at a value lower than the present host vehicle speed. Processing unit 3 calculates the recommended control input based on the target vehicle speed and generates a pattern of the control input for host vehicle 10 in the concrete form. As a result, processing unit 3 produces the pattern that host vehicle 10 is decelerated and changes the traveling lane to the right side lane 6 seconds later, as shown in Fig. 19A. Further, display unit 4 displays a command value of recommended control input ux in the form of a bar graph vertically extended from a center of acceleration 0 at the left hand side of the displayed image, as shown in Fig. 19B. Since the deceleration is commended, a bar directed in the downward direction is displayed on display unit 3. The lane change execution pattern based on uy is shown at the right hand side of the image displayed by display unit 4 as shown in Fig. 19B.
[0161] As discussed above, the lane change assist system of the third embodiment according to the present teaching comprises the vehicle-group behavior predicting means for predicting a future behavior of host vehicle 10 and surrounding vehicles, the control input evaluating means for mathematically evaluating the properness of the manipulation of host vehicle 10 from the predicted surrounding vehicle group behavior due to the manipulation of host vehicle 10, the recommended control input producing means for calculating a desired acceleration/deceleration manipulation and a pattern of a lane change operation of host vehicle 10 using the vehicle group behavior predicting means and the control input evaluating means. Further, the control input evaluating means has an evaluation criterion that it is preferable that a difference between is the host vehicle speed of host vehicle 10 and the set vehicle speed (which is of a controllable parameter). The set vehicle speed of the control input evaluating means is set at the target vehicle speed calculated by the target vehicle speed setting means 3d. The recommended control input producing means 3e includes the vehicle group behavior predicting means and the control input evaluating means.
[0162] Since the recommended control input producing means 3e converts the target vehicle speed to the pattern showing the change of acceleration from the present vehicle speed to the target vehicle speed and the pattern showing the lane change which indicates concrete control inputs, the lane change assist system can provide the concrete assist information to the driver. By producing and displaying the recommendation directly related to the manipulation of host vehicle 10, it becomes possible to provide the concrete and intuitive assist information to the driver. Therefore, the lane change assist system of the third embodiment according to the present teaching executes the effective assist of the lane change.
1. A lane change assist system comprising:
a host vehicle state detecting device (2) that detects a traveling condition of a host vehicle (10);
a surrounding vehicle detecting device (1a, 1b, 1c) that detects other vehicle (11,12) located around the host vehicle (10);
a lane detecting device (1d) that detects a lane around the host vehicle (10); and
a processing unit (3) arranged
to set a target lane to which the host vehicle (10) change a traveling lane from the detected lane,
to determine a start and an ending of a lane change assist,
to evaluate a possibility of a lane change to the target lane, on the basis of a prediction of behaviour of the host vehicle (10) and other vehicle (11,12) located around the host vehicle (10), and
to select a target vehicle speed of the host vehicle (10),
characterized in that
the processing unit (3) is further arranged
to set a predicted period (T) for the evaluation of a lane change to the target lane, on the basis of the prediction, and
to obtain an appropriate speed range (Vp) in which the host vehicle (10) is capable of executing the lane change during the predicted period (T) for each of gaps (G0,G1,G2) between other vehicles (11,12) traveling on the target lane, and
to select the target vehicle speed of the host vehicle (10) from the appropriate speed range (Vp).
2. A lane change assist system according to claim 1, characterized by a turn indicator (5) manipulated by a driver of the host vehicle (10), the processing
unit (3) is further arranged to determine the target lane, and the start and ending
of the predicted period (T), on the basis of a signal outputted from the turn indicator
(5).
3. A lane change assist system according to claim 1 or 2, characterized by a lane decreased point detecting device (6, 7) that detects a lane decreased point
at which a number of lanes ahead of the host vehicle (10) is decreased, the lane decreased
point detecting device sends information indicative of a distance between the host
vehicle (10) and the lane decreased point and a lane decreased at the lane decreased
point, wherein the processing unit (3) sets an adjacent lane as the target lane and
starts the lane change assist when the host vehicle (10) is put in a forcible lane
change condition in which the distance between the host vehicle (10) and the lane
decreased point is smaller than a predetermined distance and the lane on which the
host vehicle (10) travels is the decreased lane, and the processing unit (3) is further
arranged to terminate the lane change assist when it is determined that a lane change
to the target lane is completed.
4. A lane change assist system according to one of claims 1 to 3, characterized in that the processing unit (3) is further arranged to set an end of the predicted period
(T) at a time at which a predetermined target time period elapsed from a time that
the lane change assist is started and to extend the end of the predicted period (T)
when the forcible lane change condition is not satisfied.
5. A lane change assist system according to claim 3, characterized in that the processing unit (3) is further arranged to set an end of the predicted period
(T) at a predicted time at which the host vehicle (10) will reach a point short of
the lane decreased point by a predetermined distance time.
6. A lane change assist system according to one of claims 1 to 5, characterized in that the processing unit (3) is further arranged to obtain the appropriate speed range
(Vp) of each of the gaps (G0,G1,G2) on the basis of an inter-vehicle distance and
a relative speed between the host vehicle (10) and a vehicle producing the gap (G0,G1,G2)
on the target lane, and an inter-vehicle distance and a relative speed between the
host vehicle (10) and a preceding vehicle ahead of the host vehicle (10) on the traveling
lane.
7. A lane change assist system according to one of claims 1 to 6, characterized in that the processing unit (3) is further arranged to limit the appropriate speed range
(Vp) by an upper limit and a lower limit which are previously set.
8. A lane change assist system according to one of claims 1 to 7, characterized in that the processing unit (3) is further arranged to set the target vehicle speed on the
basis of at least a criterion that a difference between the host vehicle speed and
the target vehicle speed is small.
9. A lane change assist system according to one of claims 1 to 8, characterized in that the processing unit (3) is further arranged to set the appropriate speed range (Vp)
at a speed range (Vp) by which the host vehicle (10) avoids an excessive approach
to a preceding vehicle ahead of the host vehicle (10) on the traveling lane and to
select the target vehicle speed from the set appropriate speed range (Vp) when the
appropriate speed range (Vp) is not found and a forcible lane change condition of
requesting a forcible lane change is not satisfied.
10. A lane change assist system according to one of claims 1 to 9, characterized in that the processing unit (3) is further arranged to set the target vehicle speed at a
vehicle speed by which the host vehicle (10) stops short of the lane decreased point
by a deceleration smaller than a predetermined value when the appropriate speed range
(Vp) is not found and a forcible lane change condition of requesting a forcible lane
change is satisfied.
11. A lane change assist system according to one of claims 1 to 10, characterized by an alarm device for generating an alarm for a driver of the host vehicle (10), the
alarm device generating the alarm when the appropriate speed range (Vp) is not found.
12. A lane change assist system according to one of claims 1 to 11, characterized by a display unit (4) for displaying the target vehicle speed, the display unit (4)
displaying the target vehicle speed calculated by the processing unit (3).
13. A lane change assist system according to one of claims 1 to 12, characterized by a vehicle speed control system (8, 9, 14) for controlling the host vehicle speed
at a speed-control target vehicle speed, the vehicle speed control system employing
the target vehicle speed as the speed-control target vehicle speed.
14. A lane change assist system according to one of claims 1 to 13, characterized in that the processing unit (3) is further arranged to predict future behaviors of the host
vehicle (10) and other vehicle (11,12) around the host vehicle (10) to mathematically
evaluate a control input of the host vehicle (10) from the future behaviors produced
by the control input, to obtain a pattern of a recommended acceleration/deceleration
manipulation of the host vehicle (10) and a pattern of a lane change operation of
the host vehicle (10) from the predicted future behaviors and the future vehicle group
behaviors and the evaluation of the control input,
wherein the processing unit (3) is further arranged to have an evaluation criterion of evaluating a set vehicle speed of a controllable parameter from a smallness of a difference between the host vehicle speed and the set vehicle speed, and to set the set vehicle speed as the target vehicle speed.
wherein the processing unit (3) is further arranged to have an evaluation criterion of evaluating a set vehicle speed of a controllable parameter from a smallness of a difference between the host vehicle speed and the set vehicle speed, and to set the set vehicle speed as the target vehicle speed.
15. A method of assisting a lane change of a host vehicle (10), comprising:
detecting a traveling condition of a host vehicle (10);
detecting other vehicle (11,12) located around the host vehicle (10);
detecting a lane around the host vehicle (10);
executing a setting of a target lane to which the host vehicle (10) moves and
a determination of a start and an ending of a lane change assist; ' evaluating a possibility of a lane change to the target lane, on the basis of a prediction of behaviour of the host vehicle (10) and other vehicle (11,12) located around the host vehicle (10), and
selecting a target vehicle speed of the host vehicle (10),
characterized by
setting a predicted period (T) for an evaluation of a lane change to the target lane on the basis of a prediction,
obtaining an appropriate speed range (Vp) in which the host vehicle (10) is capable of executing the lane change during the predicted period (T) for each of gaps (G0,G1,G2) between other vehicles (11,12) traveling on the target lane; and
selecting the target vehicle speed of the host vehicle (10) from the appropriate speed range (Vp).
1. Spurwechselunterstützungssystem, aufweisend:
eine Grundfahrzeug- Zustandserfassungsvorrichtung (2), die einen Fahrzustand eines Grundfahrzeuges (10) erfasst;
eine Umgebungsfahrzeug- Erfassungsvorrichtung (1a, 1b, 1c), die ein weiteres Fahrzeug (11, 12), das sich in der Nähe des Grundfahrzeuges (10) befindet, erfasst;
eine Spurerfassungsvorrichtung (1d), die eine Spur in der Nähe des Grundfahrzeuges (10) erfasst; und
eine Verarbeitungseinheit (3), angeordnet
um eine Zielspur festzulegen, zu der das Grundfahrzeug (10) seine Fahrspur von der erfassten Spur verändert,
um einen Start und ein Ende einer Spunrvechselunterstützung zu bestimmen,
um eine Möglichkeit eines Spurwechsels auf die Zielspur auf der Grundlage einer Vorhersage des Verhaltens des Grundfahrzeuges (10) und des weiteren Fahrzeuges (11, 12), das sich in der Nähe des Grundfahrzeug (10) befindet, abzuschätzen, und
um eine Ziel- Fahrzeuggeschwindigkeit des Grundfahrzeuges (10) auszuwählen,
dadurch gekennzeichnet, dass
die Verarbeitungseinheit (3) außerdem angeordnet ist, eine vorbestimmte Zeitdauer (T) für die Abschätzung eines Spurwechsels zu der Zielspur auf der Grundlage der Vorhersage festzulegen, und
um einen angemessenen Geschwindigkeitsbereich (Vp) zu erhalten, in dem das Grundfahrzeug (10) in der Lage ist, den Spurwechsel während der vorbestimmten Zeitdauer (T) für jede der Lücken (G0, G1, G2) zwischen anderen Fahrzeugen (11, 12), die auf der Zielspur fahren, auszuführen, und
um die Ziel- Fahrzeuggeschwindigkeit des Grundfahrzeuges (10) aus dem angemessenen Geschwindigkeitsbereich (Vp) festzulegen.
2. Spurwechselunterstützungssystem nach Anspruch 1, gekennzeichnet durch einen Abbiegeanzeiger (5), betätigt durch einen Fahrer des Grundfahrzeuges (10), wobei die Verarbeitungseinheit (3) außerdem
angeordnet ist, die Zielspur und den Start und das Ende der Zeitdauer (T) auf der
Grundlage eines Signales, ausgegeben von dem Abbiegeanzeiger (5), zu bestimmen.
3. Spurwechselunterstützungssystem nach Anspruch 1 oder 2, gekennzeichnet durch eine Spurverminderungspunkt- Erfassungsvorrichtung (6, 7), die einen Spurverminderungspunkt
erfasst, bei dem eine Anzahl von Spuren voraus des Grundfahrzeuges (10) vermindert
wird, wobei die Spurverminderungspunkt- Erfassungsvorrichtung eine Information sendet,
die einen Abstand zwischen dem Grundfahrzeug (10) und dem Spurverminderungspunkt und
einer Spur, vermindert an dem Spurverminderungspunkt, anzeigt, wobei die Verarbeitungseinheit
(3) eine benachbarte Spur als die Zielspur festlegt und die Spurwechselunterstützung
startet, wenn das Grundfahrzeug (10) in einen zwangsweisen Spurwechselzustand gebracht
worden ist, in dem der Abstand zwischen dem Grundfahrzeug (10) und dem Spurverminderungspunkt
kleiner als ein vorbestimmter Abstand und der Spur ist, auf der das Grundfahrzeug
(10) in der verminderten Spur fährt, und die Verarbeitungseinheit (3) außerdem angeordnet
ist, die Spurwechselunterstützung zu beenden, wenn es festgestellt wird, dass ein
Spurwechsel zu der Zielspur abgeschlossen ist.
4. Spurwechselunterstützungssystem nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, dass die Verarbeitungseinheit (3) außerdem angeordnet ist, ein Ende der vorbestimmten
Zeitdauer (T) zu einem Zeitpunkt festzulegen, bei dem eine vorbestimmte Ziel- Zeitdauer
von einem Zeitpunkt verstrichen ist, wenn die Spurwechselunterstützung gestartet ist,
und um das Ende der vorbestimmten Zeitdauer (T) zu verlängern, wenn die zwangsweise
Spurwechselbedingung erfüllt ist.
5. Spurwechselunterstützungssystem nach Anspruch 3, dadurch gekennzeichnet, dass die Verarbeitungseinheit (3) außerdem angeordnet ist, ein Ende der vorbestimmten
Zeitdauer (T) zu einem vorbestimmten Zeitpunkt, um eine vorbestimmte Abstandszeit
festzulegen, bei der das Grundfahrzeug (10) einen Punkt kurz vor dem Spurverminderungspunkt
erreicht.
6. Spurwechselunterstützungssystem nach einem der Ansprüche 1 bis 5, dadurch gekennzeichnet, dass die Verarbeitungseinheit (3) außerdem angeordnet ist, einen angemessenen Geschwindigkeitsbereich
(Vp) für jede der Lücken (G0, G1, G2) auf der Grundlage eines Zwischen- Fahrzeugabstandes
und einer relativen Geschwindigkeit zwischen dem Grundfahrzeug (10) und einem Fahrzeug,
das die Lücke (G0, G1, G2) auf der Zielspur erzeugt, und einem Zwischen- Fahrzeugabstand
und einer relativen Geschwindigkeit zwischen dem Grundfahrzeug (10) und einem vorausfahrenden
Fahrzeug vor dem Grundfahrzeug (10) auf der Fahrspur, zu erhalten.
7. Spurwechselunterstützungssystem nach einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, dass die Verarbeitungseinheit (3) außerdem angeordnet ist, den angemessenen Geschwindigkeitsbereich
(Vp) durch eine obere Grenze und eine untere Grenze, die zuvor festgelegt worden sind,
zu begrenzen.
8. Spurwechselunterstützungssystem nach einem der Ansprüche 1 bis 7, dadurch gekennzeichnet, dass die Verarbeitungseinheit (3) außerdem angeordnet ist, die Ziel- Fahrzeuggeschwindigkeit
auf der Grundlage von zumindest einem Kriterium festzulegen, dass eine Differenz zwischen
der Geschwindigkeit des Grundfahrzeuges und der Ziel- Fahrzeuggeschwindigkeit klein
ist.
9. Spurwechselunterstützungssystem nach einem der Ansprüche 1 bis 8, dadurch gekennzeichnet, dass die Verarbeitungseinheit (3) außerdem angeordnet ist, einen angemessenen Geschwindigkeitsbereich
(Vp) in einem Geschwindigkeitsbereich (Vp) festzulegen, bei dem das Grundfahrzeug
(10) ein übermäßiges Annähern an ein vorausfahrendes Fahrzeug voraus des Grundfahrzeuges
(10) auf der Fahrspur vermeidet und um die Ziel- Fahrzeuggeschwindigkeit aus dem festgelegten
angemessenen Geschwindigkeitsbereich (Vp) auszuwählen, wenn der angemessene Geschwindigkeitsbereich
(Vp) nicht gefunden worden ist und einer zwangsweise Spurwechselbedingung des Anforderns
eines zwangsweise Spurwechsels nicht erfüllt ist.
10. Spurwechselunterstützungssystem nach einem der Ansprüche 1 bis 9, dadurch gekennzeichnet, dass die Verarbeitungseinheit (3) außerdem angeordnet ist, die Ziel- Fahrzeuggeschwindigkeit
auf eine Fahrzeuggeschwindigkeit festzulegen, durch die das Grundfahrzeug (10) kurz
von dem Spurverminderungspunkt bei einem Abbremsen kleiner als ein vorbestimmter Wert
stoppt, wenn der angemessene Geschwindigkeitsbereich (Vp) nicht gefunden worden ist
und eine zwangsweise Spurwechselbedingung nach Anfordern eines zwangsweisen Spurwechsels
erfüllt ist.
11. Spurwechselunterstützungssystem nach einem der Ansprüche 1 bis 10, gekennzeichnet durch eine Alarmvorrichtung zum Erzeugen eines Alarms für einen Fahrer des Grundfahrzeuges
(10), wobei die Alarmvorrichtung den Alarm erzeugt, wenn der angemessene Geschwindigkeitsbereich
(Vp) nicht gefunden worden ist.
12. Spurwechselunterstützungssystem nach einem der Ansprüche 1 bis 11, gekennzeichnet durch eine Anzeigeeinheit (4) zum Anzeigen der Ziel- Fahrzeuggeschwindigkeit, wobei die
Anzeigeeinheit (4) die Ziel- Fahrzeuggeschwindigkeit, berechnet durch die Verarbeitungseinheit (3), anzeigt.
13. Spurwechselunterstützungssystem nach einem der Ansprüche 1 bis 12, gekennzeichnet durch ein Fahrzeuggeschwindigkeits- Steuerungssystem (8, 9, 14) zum Steuern der Geschwindigkeit
des Grundfahrzeuges auf eine Geschwindigkeitssteuerungs- Zielfahrzeuggeschwindigkeit,
wobei das Fahrzeuggeschwindigkeits- Steuerungssystem die Ziel- Fahrzeuggeschwindigkeit
als die Geschwindigkeitssteuerungs- Zielfahrzeuggeschwindigkeit verwendet.
14. Spurwechselunterstützungssystem nach einem der Ansprüche 1 bis 13, dadurch gekennzeichnet, dass die Verarbeitungseinheit (3) außerdem angeordnet ist, die zukünftige Verhaltensmuster
des Grundfahrzeuges (10) und anderer Fahrzeuge (11, 12) in der Nähe des Grundfahrzeuges
(10) vorherzusagen, um mathematisch eine Steuerungseingabe des Grundfahrzeuges (10)
aus den zukünftigen Verhaltensmustern, erzeugt durch die Steuerungseingabe, abzuschätzen,
um ein Muster einer empfohlenen Beschleunigungs- / Abbremsungs- Betätigung des Grundfahrzeuges
(10) zu erhalten und ein Muster eines Spurwechselvorganges des Grundfahrzeuges (10)
aus den vorhergesagten zukünftigen Verhaltensmustern und den zukünftigen Fahrzeuggruppenverhalten
und der Bewertung der Steuerungseinheit,
wobei die Verarbeitungseinheit (3) außerdem angeordnet ist, ein Bewertungskriterium der Bewertung einer festgelegten Fahrzeuggeschwindigkeit eines steuerbaren Parameters aus einer Kleinheit einer Differenz zwischen der Geschwindigkeit des Grundfahrzeuges und der festgelegten Fahrzeuggeschwindigkeit zu haben,
und um die festgelegte Fahrzeuggeschwindigkeit als die Ziel- Fahrzeuggeschwindigkeit festzulegen.
wobei die Verarbeitungseinheit (3) außerdem angeordnet ist, ein Bewertungskriterium der Bewertung einer festgelegten Fahrzeuggeschwindigkeit eines steuerbaren Parameters aus einer Kleinheit einer Differenz zwischen der Geschwindigkeit des Grundfahrzeuges und der festgelegten Fahrzeuggeschwindigkeit zu haben,
und um die festgelegte Fahrzeuggeschwindigkeit als die Ziel- Fahrzeuggeschwindigkeit festzulegen.
15. Verfahren zum Unterstützen eines Spurwechsels eines Grundfahrzeuges (10), aufweisend:
Erfassen eines Fahrzustandes eines Grundfahrzeuges (10);
Erfassen weiter Fahrzeuge (11, 12), in der Nähe des Grundfahrzeuges (10);
Erfassen einer Spur um das Grundfahrzeug (10);
Ausführen eines Festlegens einer Ziel- Spur, zu der sich das Grundfahrzeug (10) bewegt und einer Bestimmung eines Beginns und eines Beendens einer Spurwechselunterstützung;
Bewertung einer Möglichkeit eines Spurwechsels auf die Ziel- Spur auf der Grundlage einer Vorhersage des Verhaltens des Grundfahrzeuges (10) und der weiteren Fahrzeuge (11, 12), die sich in der Nähe des Grundfahrzeuges (10) befinden, und
Auswählen einer Ziel- Fahrzeuggeschwindigkeit des Grundfahrzeuges (10),
gekennzeichnet durch
Festlegen einer vorhergesagten Zeitdauer (T) für eine Bewertung eines Spurwechsels auf die Ziel- Spur auf der Grundlage einer Vorhersage,
Erhalten eines angemessenen Geschwindigkeitsbereiches (Vp), in dem das Grundfahrzeug (10) in der Lage ist, den Spurwechsel während der vorhergesagten Zeitdauer (T) für jede der Lücken (g0, G1, G2) zwischen weiteren Fahrzeugen(11, 12), die auf der Ziel- Spur fahren, zu vollziehen; und
Auswählen der Ziel- Fahrzeuggeschwindigkeit des Grundfahrzeuges (10) aus dem angemessenen Geschwindigkeitsbereich (Vp).
1. Système d'assistance au changement de voie comprenant:
un dispositif de détection de l'état d'un véhicule hôte (2) qui détecte un état de déplacement d'un véhicule hôte (10);
un dispositif de détection de véhicule environnant (1a, 1b, 1c) qui détecte un autre véhicule (11, 12) situé autour du véhicule hôte (10);
un dispositif de détection de voie (1d) qui détecte une voie autour du véhicule hôte (10); et
une unité de traitement (3) agencée pour établir une voie cible vers laquelle le véhicule hôte (10) change une voie de déplacement depuis la voie détectée,
pour déterminer un début et une fin de l'assistance au changement de voie,
pour évaluer une possibilité d'un changement de voie à la voie cible, sur la base d'une prédiction de comportement du véhicule hôte (10) et de l'autre véhicule (11, 12), situé autour du véhicule hôte (10), et
pour sélectionner une vitesse de véhicule cible du véhicule hôte (10), caractérisé en ce que
l'unité de traitement (3) est agencée en outre
pour établir une période prédite (T) pour l'évaluation d'un changement de voie à la voie cible, sur la base de la prédiction, et
pour obtenir une plage de vitesse appropriée (Vp) dans laquelle le véhicule hôte (10) est apte à exécuter le changement de voie durant la période prédite (T) pour chacun des espaces (G0, G1, G2) entre d'autres véhicules (11, 12) se déplaçant sur la voie cible, et
pour sélectionner la vitesse de véhicule cible du véhicule hôte (10) de la plage de vitesse appropriée (Vp).
2. Système d'assistance au changement de voie selon la revendication 1, caractérisé par un indicateur de virage (5) manipulé par un conducteur du véhicule hôte (10), l'unité
de traitement (3) est agencée en outre pour déterminer la voie cible, et le début
et la fin de la période prédite (T), sur la base d'un signal émis par l'indicateur
de virage (5).
3. Système d'assistance au changement de voie selon la revendication 1 ou 2, caractérisé par un dispositif de détection de point diminué de voies (6, 7) qui détecte un point
diminué de voies auquel un nombre de voies en amont du véhicule hôte (10) est diminué,
le dispositif de détection de point diminué de voies transmet des informations indiquant
une distance entre le véhicule hôte (10) et le point diminué de voies et une voie
diminuée au point de diminution de voie, où l'unité de traitement (3) établit une
voie adjacente comme voie cible et commence l'assistance au changement de voie lorsque
le véhicule hôte (10) est mis dans un état de changement de voie forcé dans lequel
la distance entre le véhicule hôte (10) et le point diminué de voies est plus petite
qu'une distance prédéterminée et la voie sur laquelle le véhicule hôte (10) se déplace
est la voie diminuée, et l'unité de traitement (3) est agencée en outre pour terminer
l'assistance au changement de voie lorsqu'il est établi qu'un changement de voie à
la voie cible est achevé.
4. Système d'assistance au changement de voie selon l'une des revendications 1 à 3, caractérisé en ce que l'unité de traitement (3) est agencée en outre pour fixer une extrémité de la période
prédite (T) à un temps auquel une période de temps cible prédéterminée qui s'est écoulée
depuis un temps où l'assistance au changement de voie est démarrée et pour étendre
la fin de la période prédite (7) lorsque l'état de changement de voie forcé n'est
pas satisfait.
5. Système d'assistance au changement de voie selon la revendication 3, caractérisé en ce que l'unité de traitement (3) est agencée en outre pour fixer une fin de la période prédite
(T) à un temps prédit où le véhicule hôte (10) atteindra un point peu avant le point
diminué de voies d'un temps de distance prédéterminé.
6. Système d'assistance au changement de voie selon l'une des revendications 1 à 5, caractérisé en ce que l'unité de traitement (3) est agencée en outre pour obtenir la plage de vitesse appropriée
(Vp) de chacun des espaces (G0, G1, G2) sur la base d'une distance entre les véhicules
et une vitesse relative entre le véhicule hôte (10) et un véhicule produisant l'espace
(G0, G1, G2) sur la voie cible, et une distance entre les véhicules et une vitesse
relative entre le véhicule hôte (10) et un véhicule précédent en amont du véhicule
hôte (10) sur la voie de déplacement.
7. Système d'assistance au changement de voie selon l'une des revendications 1 à 6, caractérisé en ce que l'unité de traitement (3) est agencée en outre pour limiter la plage de vitesse appropriée
(Vp) par une limite supérieure et une limite inférieure qui sont réglées préalablement.
8. Système d'assistance au changement de voie selon l'une des revendications 1 à 7, caractérisé en ce que l'unité de traitement (3) est agencée en outre pour établir la vitesse cible du véhicule
sur la base d'au moins un critère, à savoir qu'une différence entre la vitesse du
véhicule hôte et la vitesse du véhicule cible est petite.
9. Système d'assistance au changement de voie selon l'une des revendications 1 à 8, caractérisé en ce que l'unité de traitement (3) est agencée en outre pour établir la plage de vitesse appropriée
(Vp) à une plage de vitesse (Vp) par laquelle le véhicule hôte (10) évite une approche
excessive à un véhicule précédent en amont du véhicule hôte (10) sur la voie de déplacement
et pour sélectionner la vitesse de véhicule cible dans une plage de vitesse appropriée
réglée (Vp) lorsque la plage de vitesse appropriée (Vp) n'est pas trouvée et qu'un
état de changement de voie forcé demandant un changement de voie forcé n'est pas satisfait.
10. Système d'assistance au changement de voie selon l'une des revendications 1 à 9, caractérisé en ce que l'unité de traitement (3) est agencée en outre pour régler la vitesse cible du véhicule
à une vitesse de véhicule par laquelle le véhicule hôte (10) s'arrête peu avant le
point diminué de voies par une décélération plus petite qu'une valeur prédéterminée
lorsque la plage de vitesse appropriée (Vp) n'est pas trouvée et qu'un état de changement
de voie forcé demandant un changement de voie forcé est satisfait.
11. Système d'assistance au changement de voie selon l'une des revendications 1 à 10,
caractérisé par un dispositif d'alarme pour produire une alarme pour un conducteur du véhicule hôte
(10), le dispositif d'alarme produisant l'alarme lorsque la plage de vitesse appropriée
(Vp) n'est pas trouvée.
12. Système d'assistance au changement de voie selon l'une des revendications 1 à 11,
caractérisé par une unité d'affichage (4) pour afficher la vitesse cible du véhicule, l'unité d'affichage
(4) affichant la vitesse cible du véhicule calculée par l'unité de traitement (3).
13. Système d'assistance au changement de voie selon l'une des revendications 1 à 12,
caractérisé par un système de commande de vitesse de véhicule (8, 9, 14) pour commander la vitesse
du véhicule hôte à une vitesse de véhicule cible à commande de vitesse, le système
de commande de vitesse de véhicule utilisant la vitesse cible du véhicule comme vitesse
de véhicule cible à commande de vitesse.
14. Système d'assistance au changement de voie selon l'une des revendications 1 à 13,
caractérisé en ce que l'unité de traitement (3) est agencée en outre pour prédire des comportements futurs
du véhicule hôte (10) et de l'autre véhicule (11, 12) autour du véhicule hôte (10)
pour évaluer mathématiquement une entrée de commande du véhicule hôte (10) des comportements
futurs produits par l'unité de commande, pour obtenir un modèle d'une manipulation
d'accélération/décélération recommandée du véhicule hôte (10) et un modèle d'une opération
de changement de voie du véhicule hôte (10) des comportements futurs prédits et des
comportements de groupes de véhicules futurs et l'évaluation de l'entrée de commande,
où l'unité de traitement (3) est agencée en outre pour avoir un critère d'évaluation pour évaluer une vitesse de véhicule réglée d'un paramètre contrôlable d'une petitesse d'une différence entre la vitesse de véhicule hôte et la vitesse de véhicule réglée, et pour régler la vitesse de véhicule réglée comme vitesse de véhicule cible.
où l'unité de traitement (3) est agencée en outre pour avoir un critère d'évaluation pour évaluer une vitesse de véhicule réglée d'un paramètre contrôlable d'une petitesse d'une différence entre la vitesse de véhicule hôte et la vitesse de véhicule réglée, et pour régler la vitesse de véhicule réglée comme vitesse de véhicule cible.
15. Procédé d'assistance au changement de voie d'un véhicule hôte (10), comprenant:
détecter un état de déplacement d'un véhicule hôte (10);
détecter un autre véhicule (11, 12) situé autour du véhicule hôte (10);
détecter une voie autour du véhicule hôte (10);
exécuter l'établissement d'une voie cible vers laquelle le véhicule hôte (10) se déplace et une détermination d'un début et d'une fin d'une assistance au changement de voie;
évaluer une possibilité d'un changement de voie à la voie cible, sur la base d'une
prédiction du comportement du véhicule hôte (10) et de l'autre véhicule (11, 12) situé
autour du véhicule hôte (10), et
sélectionner une vitesse de véhicule cible du véhicule hôte (10),
caractérisé par
le réglage d'une période prédite (T) pour une évaluation d'un changement de voie à
la voie cible sur la base d'une prédiction,
obtenir une plage de vitesse appropriée (Vp) dans laquelle le véhicule hôte (10) est
apte à exécuter les changements de voie durant la période prédite (T) pour chacun
des espaces (G0, G1, G2) entre d'autres véhicules (11, 12) se déplaçant sur la voie
cible; et
sélectionner la vitesse de véhicule cible du véhicule hôte (10) dans la plage de vitesse
appropriée (Vp).
REFERENCES CITED IN THE DESCRIPTION
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.
Patent documents cited in the description